My car is a 2012 Evo MR w/ 18k miles.

So I was at one point tuned remotely by a shop. Saw too much knock and fluctations in my A/F that wasn't on its way to being fixed with each revision. I took it upon myself to begin trying to dial in my own A/F curve and got it pretty leveled out but I keep sing some spikes and dropoffs that I cannot account for with ECU Flash. From 4500-4700 rpms I would see a drop off from 11.5 to 11.0 then back up to 11.5 or a spike from 11.5 to 12.0 then back down to 11.5. Any changes I made with the High Octane fuel map wouldn't get rid of these spikes. Pic is attached showing what I'm talking about.

So I'm at the point where I think I need to start over fresh with my stock ROM.

My mods are: ETS Intake (OEM MAF housing), ETS UICP, Hallmann Pro MBC, ETS 3" catless test pipe, Greddy SP Elite catback.

Boost is set to 23-24psi depending on air quality.

Is there anything I need to take into serious consideration before starting over with the STOCK ROM? Should I lower boost back down to 20psi, or add fuel in specific places before I begin making progressive pulls?

Any other help would be greatly appreciated, thanks gents.

--Matt

 

The car uses more than just the high octane fuel map.

You should put the car back on ecu controlled boost. MR's are never happy for long on external boost controllers.

 

Here's a stab in the dark...


1. Get hold of, install, and use RAX Fast Logging.

2. Review MAPCalcs, IMAPCalcs, MAFCalcs and ChosenCalc.

3. See if IMAPCalcs spikes up around that 4500rpm mark, with a synchronised drop in MAPCalcs.

4. The ECU will choose the "middle" of MAPCalcs/IMAPCalcs/MAFCalcs. See what ChosenCalc looks like when the spikes happen. If it jitters up or down, that's the load input causing your AFR wobbles.

5. Download the latest ROM definition from goldenevo.com.

6. Change Load multiplier end when TPS decreased by % (hysteresis) from 0.4 to 0.8 or 1.2. More details here.

7. Reflash.

8. Repeat test.


Rich

PS. Then go look at your spool-up mixtures. See here.

PPS. Go through the GST Base Map for any Ralliart ROM, and compare it in EcuFlash to the stock ROM. You'll find many, many interesting things that will keep you happily tweaking for months. 99% of it applies equally to Evo X.

 

Just patched to the RAX Fast Logging... going to make some logs tonight when traffic dies down.

Thanks for your advice. I will update.

 

Nice advice rich!